This invention relates generally to motor vehicle wheels and tires, and more particularly to blowout protection devices.
Land vehicles such as automobiles and trucks are almost uniformly equipped with air-inflated tires. These tires combine the advantages of a relatively soft ride with great maneuverability. One disadvantage of such tires is the susceptibility to punctures. If a puncture is major and is accompanied by a rapid loss of tire pressure, commonly known as a blowout, it is very easy for the driver to lose control of the vehicle. In fact, blowouts are a major cause of serious automobile accidents.
A great deal of work has been done to increase the puncture resistance of conventional tires. Most of this work has centered around the search for materials which will add to the strength of the tire. While stronger tires have evolved from this research, such tires are often typically far heavier than conventional tires, often adversely affecting the performance and gasoline consumption of the vehicle. Another disadvantage is that heavier tires are often characterized by greater heat build-up during operation, thereby decreasing the life of the tire. Excessive heat build-up has also been shown to increase fuel consumption.
At least one tire manufacture has apparently developed a heavier tire which resists punctures but which avoids the excessive heat build-up found in some such tires. This tire also allegedly has sufficient strength to support the weight of a car for a short time even after loss of air pressure. This feature enables the driver to drive to a service station in the event of a puncture, thereby doing away with the conventionally required spare tire. While this appears to have the capability of solving some of the problems discussed above, the tire undoubtedly would be quite expensive and therefore is unlikely to achieve widespread public acceptance.
Efforts by others to hasten the demise of the spare tire have centered around the use of puncture sealant stored in a pressurized can. When a tire is flattened due to a puncture, sealant is injected under pressure into the tire, thereby inflating it with pressurized air. The sealant flows into the puncture and is intended to seal same. However, unless the puncture is quite small, the sealant will merely blow through the puncture along with the pressurized air. Needless to say, the use of pressurized sealant is also limited in that it cannot be used to protect against blowouts.